Engine.



No. 768,068. PATENTED AUG. 23.19.04. W. s. MUKINNEY.

ENGINE. v f

urmorrlon rILnD un. s. 1902. Y nmmwnn un. sa, 1904.

lN0 IODEL. 2 SHEETS-SHEET 1.

OHIIIIIH HIIIII I W. S. MOKINNBY. v 1 3 ENGINE. a k

APPLIoATIoN FILED PEB. s. 1902. RENBWBD JAN. za. 1904.-

' 2 SHEETS-SHEET 2.

No. 768,068. PATENTED AUG. 23H90@ N0 MODEL.

O fa

l UNITED STATES i Patented August 23, 1904.. i I

WALTER SABIN MCKINNY, OF CHICAGO, ILLINIS.l

ENGINE.

SPECIFICATION forming part of Letters Patent No. 768,068, dated August 23, 1904. Application filed February 3, 1902. Renewed January 23, V1904. Serial Ncl 190,362. (No model.)

the following is a specification.

This invention relates to improvements in engines, and refers more specifically to improvements in the valve mechanism controlling the passageof the motive iiuid through the cylinder of the engine.

Among the salient objects of the present invention are to provide an engine of high; economy; to provide an improved valve mech-V anism which is directly controlled or actuated by the pressure of the motive iiuid; to provide a construction in which the movement of the piston operates to uncover or open a port communicating with the cylinder and leading to and operating the cut-off valve; to provide in a construction of this general character a valve which operates to shift promptly from fully-opened to fully-closed position and independently of the movement of other parts of the engine, thereby effecting substantially instantaneous admission and cut off of the motive Huid; to provide in aconstruction of this general character means for varying the position of cut-off at will; to provide means for varying the point of cut-off whichdispenses with all complicated valve-gear and effects the variable cut-off by the simple change in registering position of a valve member controlling the cut-off at all times; to pro,

vide in a construction of this general character a mechanism for automatically effecting wthe cut-off as determined by the load require-1 ments and through the medium of any suitable type of governor; to providev an im' proved exhaust-valve mechanism actuated by pressure directly from the cylinder of the engine and likewise characterized by being constructed to shift from fully-closed to fullyopen position, and vice versa, independently of the movement of other parts of the engine; to provide a simple and improved mechanism for effecting a reversal of the engine; to provide an engine which is not only reversible,

but in which the parts controlling the movement of the piston in each direction are du-y inafter described, and more particularly pointed out in the appended claims, and the same plicates or substantial duplicates of each other andI are symmetrically, but reversely, ar' ranged; to provide va construction in which the entire valve-gear is or may he self-contained Within the body of the cylinder, and in 'general to provide a construction which may be economically manufactured, in which the parts may be machined to accuracy with the greatest facility, which-Will he durable and cannot readily vget out of repair or adjustment, and which has no intricate mechanismv requiring special skill or knowledge to properly operate the engine.

The invention consists in the matters herewill be more readily Aunderstood from the fol# lowing description by reference to the vaccompanying drawings, forming a part of the description, and in Which- Figure l is an axial sectional View, taken on line l l of Fig..5, of the cylinder of an engine embodying a preferred form of my invention. Fig. 2 is a side elevation of the part shown inV Fig. 1. Fig. 3 is a longitudinal sectional view taken -on line 3 3v of Fig. 2. Fig. iis a transverse'sectional view taken on line .44 of Fig. 2 vand looking in thedirection of the arrows., Fig. 5 is an end. elevation. Fig. 6is a fragmentary detail showing the .relative arrangement of the valve-,tubes and worm which is arranged to actuate the same. Fig. 7 is aside elevation of the cylinder and part of the engine-frame of an embodiment of my invention in which the point of cut-off .is determined automatically by a governor and showingparticularly the arrangement of the governor mechanism. Fig. 8 is a longitudinal or axial; section taken vertically through the cylinder shown in Fig. 7 and Fig. V9 is a fragmentary detail showing the relation of the valve-tube to the worm which operates the same.

Referring first to the construction shown in Figs. 1 to 6, inclusive, l designates as a whole an engine-cylinder, within which is arranged to operate a piston 2, which imparts movement to a piston-rod 3 in the ordinary manner. At each end the cylinder is provided with an inlet-port, as 4, which ports in the preferred 1 00 AIo construction shown herein communicate with a common inlet-chamber 5,.formed in the main body of the cylinder outside of the main chamber to extend practically the full length of the cylinder, as shown clearly in Fig. 1. rlhe passages between the inlet-chamber 5 and the two `ports 4C at the respective ends of the cylinder are controlled by means of valves, (respectively designated as a whole 6 and 7,) which valves are of open-piston or ring form and areseated in suitable chambers formed in the body of the cylinder, preferably in oppositely-disposed relation, as seen clearly in the several figures of the drawings. In the preferred embodiment shown herein these valves are cylindric slid e-valves seated in correspondingly-shaped valve-chambers 8 and 9, each valve-chamber being provided at a point in y register with the valve-body when'the latter is ventially-extending enlargement, as 1() and 11,

shifted to its outermost limit'withl a circumferwhich eommunicateswith the interior of the cylinder through a passage (designated 12,) and terminating in one of the ports 4 hereinbefore referred to, these passages 12 being extended in the Asame plane with the annular enlarge- 'mentsy 10 and 11.

The communications extending from the inlet-chamber 5 t0 the respective valve-chambers 6 and 7 are, as best 'shown in Fig. L1, arranged to extend from the respective end portions of the inlet-chamber 'at an abrupt angle outwardly, as indicated at 12', so as to communicate with the inner ends of the cylindric.valve-chambers, the motive fluid passing from the passages 12" directly through the ring-like piston-valve to the pas-y sage 12 when said valves are in open position.

Obviously -when the valves are shifted to their outermost limits, so as to overlap the annular -enlargements 10` and 11, the communicationy between the inlet chamber and cylinder will be closed.- In order that the piston-valves-may -reciprocate across the ports communicating with their-chambers, diagonally-disposed ribs or guides are extended across said passages, Aas indicated at113.

: Fiach inlet-valve is provided with astem 14, with which it is rigidly connected and which gste'm is arranged to extend .inwardly into a piston-chamber 15, wherein it is connected yswith a piston 17, which serves to actuate the valve, as willrhereinafterappear. As a convenient'construction the piston-chambers 15 are formed in the inner ends of cylindric pluglike `members 18 and 18', which are seated in reduced extensions -19 and 19' of the respective valve-chambers 8 and 9, said .extensions being preferably'concentrically disposed with the valve-chambers. w

Y At their inner ends the piston-chambers 15 communicate with tubular valve-chambers 2O and 20, which preferably extendparallel with. the axis of the main cylinder and are so formed within the cylinder-body as to avoid interfering with each other, as shown bestin Fig.

Within the tubular valve-cliambers 2O and 20, respectively, are arranged tubular valve members 21 andv 22, each having the ferm of an open-ended tube provided with a series of inlet-apertures 23 and 23', arranged to extend in a spirally -disposed row throughout the length of the valve member. Through the inner side wall of the cylinder at points radially opposite the respective valve-chambers 2O and 20 are formed two rows or series of ports 24, which ports are severally arranged to register with the corresponding apertures 23 or 28' of the valve-tubes when the latter are rotated into proper angular relation therewith, and said tubular valve members terminate short of or are interrupted opposite the inner ends of the respective piston-chambers 15, so that said piston-chambers are in open communication with the interiors of the respective valve-tubes. At their opposite ends said valve-tubes are also preferably open (although not necessarily) and communicate through ports 24 with the interior of the main cylinder. In the preferred construction shown herein the tubular valve-chambers are formed by boring inwardly from the opposite ends of the cylinder-body to the required distance and inserting the valve-tubes therein, the portions of the outer ends of said valvechambers intervening between the pistonchambers 15 and the end caps of the cylinder being' occupied by plugs 25.

The inner end of each piston-chamber 15 is placed in communication with the interior of the main cylinder at a point adjacent to the proximate end of said cylinder through passages 26, (see Figs. 1 and 3,) these passages serving to admit pressure to drive the pistons 17 in one direction, as will hereinafter appear.

Describing now the exhaust-valve mechanism, 27 designates a common exhaust-chamber, preferably formed in the body of the cylinder at a point substantially opposite the inlet-chamber 5 and arranged to extend the full length of the cylinder-body, said exhaustchamber being desirably and most economically made interiorly cylindric or circular in cross section. At points a short distance vremoved from the respective ends of the of juncture of the main central chamber 27' with the enlargements or ports 28 and 2S) are formed annular valve-seats and 30, with which are adapted to eoperatevalves 31 and 32, mounted upon a-stem 38, common to both. The stem 33 is extended at each end beyond the valves and is provided or connected with pistons 34 a'nd 35, arranged to operate in the cylindric end portions or pistonchambers 86 and 36, formed by the extensions of the exhaust-chamber 27. Each pisthe valve-tu bes.

ton-chamber 36 and 36' is placed in communication with the corresponding end of the main cylinder-chamber through a port or passage, as 37 and 37, these ports being arranged to communicate with the respectiveV pistonchambers at points longitudinally outside of or beyond the outermost limits of movement of the corresponding piston 34 or 35.

As a convenient means of rotating or setting the valve-tubes 21 and 22 to bring any desired port 23 or 23 thereof intoregister.

with the corresponding port communicating with the maincylinder I provide the exterior of each valve-tube with a worm-gear, as indicated at 38 and 38', and suitably journal in the bodyof ,the cylinder a worm-screw 39, so as to engage said worm-gears and'actuate The worm-gears 38 and 38 are of equal diameter, so that said tubes are rotated simultaneouslyv and coextensively,

-and therelative spiral arrangement of their ports 23 and 23' is such that they will be brought into register withV corresponding ports of the cylinder simultaneouslythat is -to say, if the valve-tube 21 beso rotated that its port nearest its inner end be arranged to communicate with the interior of. the cylinder the corresponding port nearest the inner or opposite end of the valve-tube 22 will likewise bein communication with the cylinder. The inlet-chamber 5 communicates with any suitable source of steam or other motive-Huid supply through an inlet-pipe 40, While the common exhaust-chamber 27 is provided with an exhaust-pipe 41, leading therefrom, asv

shown clearly in the drawings.

An understanding of the additional features of the present invention to be hereinafter described will be facilitated by a description at this point of the general operation of the engine constructed as thus far described.

Referring more particularly to Figs. 1 and 3, the parts are.therein shown in the position they assume when the piston is advancing to` Ward the left-hand end of the cylinder, in which case the exhaust is through the lefthand exhaust-port and the steam-supply controlled by the right-hand end cut-off valve 7, which is shown in open position. With the tubular valve members adjusted as shown in the x drawings the point ofv cut-off will be reached When the piston has approached toward the left-hand end of the cylinder far enough to uncover that port of the valve member 22 corresponding to the port of valve member 21 opposite which it is shown in- Fig. 1, it being remembered that the ports of valve member 22 bear the same relation to the cylinder as to those of the valve member 21 shown in section in said Fig. l-that is to say, the

point of cut-off is determined by that one of the ports of the tubular valve member which comm'unicates at itsouter or foot end with the piston-chamber 15, which controls the supplymembers are shown as communicating with the cylinder through the ports which are nearest to their inner ends; but it is tobe understood that it is the valve-tube which communicates with thel piston-chamber 15 of the particular supply-valve admitting steam which controls said valve, and the fact that the ports of the other valve member .are brought into communication with the live-steam -part of the cylinder sooner has no effect upon the operation of the particular valve at that time controlling the inlet. When the piston reaches the point of cut-off, live steam admitted to the valve member 22 passes to the piston-chamber 15 and there acts upon the piston 17 to force. the latter outwardly and with itthe valve 7,

mounted upon its stem,fthereby cutting off the steam admission. It may be explained at this point Ythat the pressure which acts to shift the piston 17 is a differential pressure, since the piston is subject to live-steam presber 22 on one side, as last explained, and

`through the passage 26 at its opposite side.

Upon its opposite side, however, a substantial part of the area of thel piston is occupied by its stem connection, so thatit lis in fact a differential piston and will therefore move in the direction of its side having lesser area. Obviously admission of live steam directly to sure upon both sides-through the valve memthe piston-chamber l5 will effect an almost instantaneous closure of the supply-valve.-

After the piston passes the point o f cut-off it continues under the expansive action of the steam until it passes the exhaust-port 28,

which, as hereinbefore mentioned, `is located some distance from the proximate end of the cylinder.` As soon as the piston passes'the exhaust-port the volume of exhaust Huid contained between the piston and the `end of. the cylinder toward which it is approaching is trapped and forced out throughthe passage 37, leading to the outer end of the pistonchamber 36, controlling the exhaust-valve.1

The compression rapidly raises the pressure ITO to a point above that'at the vopposite side of the piston, (which it will be observedis acting j to hold the exhaust-valve open,).whereup`on this pressure acting upon the piston v341 shifts* the exhaust-valve'into closed Vposition as to that end of the cylinder. The samecompression which operates to close the exhaust-valve at the .same time forces the motive iiuid through the passage 26 into the piston-chamber 15,. which controls the supply-valve 6 at that end ofthecylinder, thus forcing its piston 17 inwardly and .opening the supplyvalve. The return of the main piston-thereupon begins, and-'the operations during thev remaining half 1 of the cycle of movement of the engine are obviously an exact repetition of'those movements hereinbefore described,

except, of course, thatthe valve-tube member n.21l now determines the pointA of :cut-off and communication as soon as the piston passes` the registering port of that valve-tube. This, however, has noobjectionable effect upon the operation ofthe engine, since the cut-off Valve at the end of the -cylinder toward which the piston is advancing has already beeny closed and such live-steam pressure would thereforesimply act to hold it in closed position. .to thereversely-disposed valve-tube 22, howzo ever, live steam cannot obtain access to the latter .until the piston has reached the point -of cut-off. 1 i

With the construction shown in the ligures thus far described the regulation of the point 2 5 of cut-olf is determined manually by operating the worm39 through the med-ium of its hand-wheel and rotating the valve-tubes to bring that particular port of each into register vwith the corresponding port of the main cyl- 3o .inder at the particular desired point of eut-olf. In view of the spirally-disposed arrangement ofthe -ports in the valve members? it will be .obvious that as.y the valve member is rotated .to bring a succeedingport'into register that A port theretofore vin' register will be closed. In other words, if the spiral arrangement of thezports is such that the angularinterval f between adjacent ports is equal to or greater rthan the diameter of the ports only one poi't 4o will be atV any timein communication witlr 'the interior of the cylinder. It thus becomes a simple matter of rotating the worm-screw 'more or less to change the point. of cut-off to -any i point throughout practically the full 14 5ulength of tlietubular valve members, and obviously in the case of such engines as may re-` ;quire- :frequent adjustment of the cut-off point--as, for example, in an automobile- :enginethe adjustment maybe made by means 5o-of any suitable..hand-operated mechanism -ncapable of `operation vmorereadily than the worm-screwmechanism described herein. In

this same connection it is Vto 'beunderstood' s s and will be entirely7 obviousto those skilled '55 in the art thatit is only necessary that the .tubular valve members 4have relativefmove- --ment tothe series of ports affording communication with the vinterior of the main cylinder.. This relativemovement may be either rotative or reciprocatory or any other-suitable movement, and ifreciprocatoryv and rectilinear the valve members might obviously f be of any preferred form in .cross-'section as well as circular. In this same connection it is to be understood that while the particular embodiment illustrated and described herein is deemed to be a highly-eiiieient and practical embodiment of the invention, yet in the broad sense this construction is iiieiely illustrative and the principles of the invention may be embodied in various forms. It may also be noted that the most salient feature of the invention is the arrangement which provides a practically instantaneous cut-oli' of the motive fluid by direct action of the motive fluid, and especially when the construction is one in which the point of cnt-off may be varied, while the particular exhaust mechanism shown and described is a subordinate feature of the invention and not in any sense an essential one-that is to say, the exhaust of the engine might be effected and controlled by any of the common expedients well understood in the art, as, for example, it might be actuated by an eccentric in the usual manner.

It may be further remarked that the restoration of the cut-off valves to their open or admission positions is not necessarily accomplished in the peculiar manner herein described, although the mechanism lieieiii described for accomplishing this end is deemed an important feature of the invention.

Referring now to the construction shown in Fig. 7,@ seqmftm', an engine-cylinder is therein shown which is generally similar to -present instance these passages instead of being extended directly from the respective ends of the cylinder to the piston-chambers of the exliaust-cliamber are extended lirst to a two-way cock or valve 45, and thence back to the piston-chambers .46 and 47, respectively. The two-way cock is provided with crosspassages, as indicated in dotted lines at 48 and 49, which when said cock is rotated an angiilar extent equal to ninety degrees trom the position shown has the effect of crossing the ,passages 43 and 44, so that the passage 44 then communicates with the chamber 46 and the passage 43 with the chamber 47.

The reversal of the engine is accomplished by simply turning the two-way cock so as to cross the passages, thereby reversing the .order of movement of the exhaust-valves and .eated in the drawings, whereupon the engine continues to operate in its reverse direction. Describing now the mechanism whereby the point of cut-olf is controlled automatically, v50 designates a worm-screw which is intei- IOS ITO

ranged to intermesh with a slide-rack 52, i

working vertically through a guide 53. 55

-designates the lever of an ordinary ball-governor, designated asawhole 54 and mounted, steam-engine, although possessing a special .as usual, upon a suitable bracket 56 upon the 4engine and driven by means of a belt 57.

The vibrating end of the lever 55 is connected 3 with the upper end of the rack 52- by 'means of a link 58, so that movement of the governor is imparted to the rack and through the latter to the worm-screw, thereby rotating.: the valve-tube members 42 synchronously The l with the movement of the governor. ports or passages 23 of the valve-tube members are in this instance, as in the previouslydescribed construction, arranged spirally,f

while the ports 24, affording communication between said valve-'tubes and the interior of the cylinder, are in a straight row, as shown clearly in Fig. 8,

The operation of the mechanism constructed and arranged as described is probably entirely obvious, but may be briefly indicatedv by stating that the valve-tubes are so interconnected with the governor that as the speed -of the engine rises and the governor responds the valve-tubes will be rotated in a direction to open the ports leading'into the valve-tubes successively nearer and nearer to the admission end of the cylinder or toward the foot of the valve-tubes, thereby admitting less and less steam and using more expansively. vVice versa, when the load increases the governor will fall, and thus rotate the 4valve-.tubes to lengthen or advance the point of cut-off automatically. l y

It will be-seen from the foregoing description that bythe use of my invention I en-` tirely dispense with the usual valve-gear and substitute therefor simple valve .mem-bers, having comparatively slight movement, substantially all inclosed within the body of the engine, and operated, so'faras the cut-off and exhaust-valves are concerned, directly by themotive fluid. The very slight movement of any part necessary to effect the control of the motive fluid reduces the wearing effects of momentum and rapid movement to a minimum, while at ythe same time the principal parts are so constructed that the wear is distributed over large `areas and the parts are of a form capable of being readily and cheaply machined to accuracy. Moreover, the construction is such that access to all of the-parts may be readily had for inspection, renewal, or repair. The `fact that the controlling-valves are kshifted or 'operated by means of the motive -fiu'idinstead of by mechanical means enables :me to adopt a construction of valve which may .beshifted .f-romone vpositionjorlimitfof move-1 ment to the opposite instantly, thereby affording the same efficiency which has heretofore been obtainable only in valve-gears of the generaltype knownas the Corliss type, and entirely avoiding wire-drawings. and its accompanying objections.

` It willv be obvious and is to be understood that thenvention is not limited to a advantage when embodied in the form of an lautomatic variable cut-0E steam-engine, nor isthe invention in its broad sense limited tothe ,peculiar arrangement of parts herein show-n, and various modifications will` readily occur to those skilled in the art. I donot, .therefore, limit myself to the details shown and described except to the extent that they are herein claimed specifically. f I claim as my invention- 1, In an engine, ythe combination with the cylinder and piston arranged to operate therein, vof an admission-valva'means foractuating said admission-valve comprising a part mechanicallyconnected and moving with the kadmission-valve, vand two passages independent -of the main admission-passage, arranged to communicate with the cy'linderat separated points yand through which opposite sides of Asaid part moving with the admission-valve is subject to pressure, an exhaustfvalve, :and f means for actuating said exhaust-valve, functionally independent of the admission-valve,

for the purposes set .forth. .v Y

.2. In an engine, the combination with the cylinder and piston arranged to operate therein,"of an admission-valve, means for operating said admission-valve comprising a lpart mechanically connected and moving with said admission-valve and arranged within a secondary cylinder, and two passages independent `of the main admission-passageaffording communication between said secondary cylinder and main cylinder, one of saidy passages communicating with the mainA cylinder at or near the admission end thereof and the other at a point remote from the admission end, an exhaust-valve, and means for actuating said exhaustvalve, functionally independent of the vmovement of the admission-valve, :for the purpose set forth. i

3. In an. engine, the-combination with the cylinder and pistonarranged 'to operate therein, of an `admission-valve, a passage arranged to co'mmunicatewith the vcylinder ata point -at/,ornear'the admission end thereof,a second passage arranged to communicate with the cylinder at a point remote from-'said admission end, a part moving with said admis-A sion-valve and subjectto differentialgpressure through said passagesat an interval during the outstrokeof the piston toclose thevalve,

and mechanism for eecting a compression within the cylinder as the piston approaches its return limit of `movement wherebypres- .,snreis .admitted through ,the firstmentioned of said valve-passages to that side of the valveoperating member having the lesser area subject to pressure.

4. In an engine, the combination with the cylinder and piston arranged to operate therein, of an admission-valve, aseries of passages arranged to communicate with the cylinder at separated points along the travel of the piston andv forming a variable cut-off, a part moving with said admission-valve adapted to be `subjected to pressure through said passages, valve mechanism for controlling said- Vpassages, an exhaust-valve mechanism and means actuating said exhaust-valve mechanism independently of the admission-valve.

5. In an engine, the combination with the cylinder and piston arranged to operate therein, of an Vadmission-valve, a series of passages l arranged to communicate w1th the cylinder at 1 separated points along and within the limits oi' travel of the piston, a part moving with said admission-valve and adapted to be subjected to pressure through either of said passages and a valve member common to all of said passages. one of said rpassages being arranged to communicate with a part of the main cylinder Within which the exhaust iluid is trapped and compressed bythe approach of thepiston to its limit of movement in one direction, as and for the purpose set forth.

6. In an engine, the combination with the cylinder and piston arranged to operate therein, cfa separate and independently-operableA admission-valve, controlling the admission to each end of the cylinder, a series of passages for each admission-valve arranged to communicate with `the cylinder at separated points along and Within the limits of travel of the piston, a part moving with each admissionvalve and adapted to be subjectedto pres- :sure through either of said passages, and

means for e'ecting the opening of said admission-valve.

7 In an engine, the combination with the cylinder and piston arranged tooperate therein, of an admission-valve, asteam chamber or passage arranged to extend longitudinally of the cylinder, a series of ports affording communication at longitudinally-separated points between said steam chamber or passage and cylinder, a part moving with said admissionvalve, and subject to pressure through said steam chamber or passage and a movable valve therein, of an admission-valve, a tubular pas'- sage arranged to extend longitudinally ol the cylinder, a series of passages affording communication between said tubular-passage and cylinder at Various points along the travel of the piston, a part moving with said admissionvalve subject to pressure through said tubular passage and a tubular valve member arranged to {it within said tubular passage and provided with a series of ports adapted to be brought into variable register with the passages or communicating with the cylinder.and means for rotating said tubular valve member, for the purpose set forth.

9. In an engine, the combination with the cylinder and piston arranged to operate therein, of an admission-valve, a series of passages arranged to communicate with the cylinder at separated points, a part moving with said admission -1 valve and subject to pressure through said passages, valve mechanism for controlling said passages and a governor arranged to automatically control said valve mechanism.

lO. In an engine, the combination with the cylinder and piston arranged to operate therein, of an admission-valve, a plurality of passages arranged to communicate with the cylinder at longitudinally-separated points within the limits of travel of the piston, a part moving with said admission-valve and subject to pressure through said passages, avalve member common to and controlling a plurality'of said passages, a governor and interconnections between said valve member and governor whereby the latter is operated to vary the point of cut-olf substantially as dcscribed.

11. In an engine, the combination with the cylinder and piston arranged to operate therein, of an admission-valve, a tubular passage or chamber arranged to extend longitudinally of the cylinder, a series of ports or passages aording communication between the cylinder and longitudinally-extcnding' passage or chamber at points throughout the length of the latter, a piston-chamber in communication with said tubular passage, a piston arranged therein and operatively connected with said admission-valve, a tubular valve member the interior of which forms a steam-passage arranged within said tubular passage, and provided with a corresponding series of ports adapted to be brought into variable register with the ports leading to the cylinder, and means for controlling the relative position of said valve member.

152. In an engine, the combination with the cylinder and piston arranged to operate therein, of an admission-valve, a tubular passage or chamber arranged to extend longitudinally of the cylinder, a series of ports or passages alfording communication between the cylinder and longitudinally-extending passage or chamber at points throughout the length of ITO differential piston wherein the latter is the latter, a vpiston-chamber in communica-l tion with said tubular passage, a differential piston arranged Within saidv piston-chamberl and operatively connected with said admission-valve, a tubular valve member the interior of which forms a steam-passage arranged within said tubular passage, and provided with a corresponding series of ports adapted to be brought into variable register with the ports` leading to the cylinder, means for controlling the relative position of said: valve member,

and a passage affording communication between the admission end of the cylinder and that side of the piston-chamber containing tle su ject to a lesser area of pressure. n

13. In a double-acting engine, the combinationwith the cylinder and piston arranged to operate therein, of an independent admissionvalve for admitting motive fluid to each end -of said cylinder, a plurality'of passages arranged to communicate with the cylinder at separated points, and parts moving with said lrespective admission-valves subject to differential pressure through said passages, andan .exhaust-valve controlling the exhaust from each end of the cylinderand means for actuating said exhaust-valves independently of the movement of the corresponding admislsion-valves.

14. In a double-acting engine, the combination with the cylinder and piston arranged to reciprocate therein, of an independent admission-valve for admitting motive fluid to each end of said cylinder, a plurality of passagesv arranged to communicate withthe cylinder at longitudinally separated points within the limits of travel of the piston, a part moving with each of said admission-valves and subject to pressure on one side through said passages and other passages communicating with the cylinder at or adjacent to the ends thereof through which said parts moving with the respective admission-valves are subjected to pressure upon their opposite sides, an ex-` haust-valve, and means for actuating said exhaust-valve independently of the movement of either admission-valve.

15 In-a double-acting engine, the combination with thecylinder and piston arranged to reciprocate therein, of an admission-valve for admitting motive fluid toeach end of said cylinder, a plurality of passages arranged to communicate with the cylinder at longitudinally-separated points within the limits ofi travel of the piston, a part moving with each of said admission-valves and subject tolpressure on one side through said passages and other passages communicating with the cylinder at or adjacent to the ends thereof through which said parts moving with the re- `spective admission valves are subjected to pressure upon their opposite sides, and exhaust-ports communicating vwith the respective'ends of the cylinder at points within the limits of travel of the piston.

16. In an engine, the combination with they y.

cylinder and piston arranged to operate therein, of an exhaust-port communicatingwith the v cylinder at a point substantially within the limits of travel of the piston, an exhaust-valve i arranged to control said port, a passage communlcating with the cylinder between the eX.-

-haust-port andthe proximate end of the cyl-- 'inder and a part moving with the exhaustvalve and subjected to pressure through said latter passage after the piston` passes the exhaust-port. p

17. In an engine, the combination with the cylinder and piston arranged to reciprocate therein, of an exhaust-port arranged to communicate with the cylinder, at points substantially within the limits of movementot' the piston so that the latter reciprocates beyond said exhaust-port, a valve arranged to control lsaid exhaust-port, a piston-chamber and piston therein operatively connected with said exhaust-valve and a passage communicating withthe maincylinder at. a point beyond the vexhaust-port and affording communication to the piston-cylinder controlling the exhaustvalve substantially as described.

18. In a reversible engine, the combination with the cylinder. and. piston arranged to reciprocate therein, of exhaust-ports at the respective ends of the cylinder located substantially within the limits of movement of the piston so that the latter reciprocates beyond the same, valves arranged to control said several exhaust-ports, interconnections whereby said valves are connected to move into.

closed and open position alternatively, parts movingwith said 'valves and constituting in effect piston members, passages affording communication with the respective endsr of the main cylinder and the chambers within which said valve-operating piston members operate, and valve mechanism for cross-connecting said latter passages, as and for the purpose set forth.

19. In anengine, the combination with the cylinder and piston arranged to operate therein, of an admission-valve, two passages arranged to communicate with the cylinder at separatedA points, a part moving with said admission-valve and subject to differential pres-x sure throughsaid passages for controlling movement of the admlssion-valve, an exhaustport communicating with .thecylinder near one end thereof but substantially within the IIO IIS

limits of movement of they piston, ak valve arranged to control said port, a passage communicating with the cylinder `at a point beyond the exhaust-.port or at thatside of the latter toward which-V the piston is moving While exhausting through said exhaust-port, and a part moving with'the valve controlling said exhaust-port which is subjected to pressure through said last-mentioned passage after the piston passes the exhaust-port.

20. In an engine, the combination with the cylinder and piston arranged to reciprocate therein, of an admission-valve, a vplurality or' passages arranged to communicate with the cylinder at longitudinally-separated points, a

vpart moving with the admissionvalve andA Subject to di'erential pressure through said passages for controlling movement or' the admission-valve, an exhaust-port communieat' ing With the cylinder near one end thereoil but -substantially Within the limits of movement of the piston, a valve arranged to control said port, a passage communicating with the cylinder at a point beyond the exhaust-port or at that side of the latter toward Which the pisvt0n is moving While exhausting through said exhaust-port, and a part moving with the valve controlling said exhaust-port which is subjected to pressure through said last-mentioned passage after the piston passes the eX- haust-port.

2l. In adouble-acting engine, the combination with the cylinder and piston arranged to reciprocate therein, of admission-valves ar- -ranged to control admissionjof motive iuid to ,haust-ports, interconnections whereby said exhaust-valves are connected to move alternately into open and closed positions, a part moving with each exhaust-valve and constituting in effect a piston, chambers within which said piston members are respectively arranged, passages affording communication between said chambers and the corresponding end portions of the main cylinder and a twoway valve arranged to cross-connect said passages substantially as shown.

22. In an engine, the combination with the cylinder, piston arranged to operate therein and source ot' motive-Huid supply, ot' an admission-valve controlling the supply of motive fluid, a differential piston forming a part of or moving with said admission-valve subject upon both sides to the direct pressure of the motive liuid, an independently-operated exhaust-valve mechanism and means for varying the point of cut-o through the medium of said differential piston.

23. In an engine, the combination with the cylinder', piston arranged to operate therein and source of motive-fluid supply, of an admission-valve controlling the supply of motive iiuid, a diii'erential piston forming a part of or moving with said admission-valve, and having its side oi' lesser area subject to the motive-Huid pressure at all times during admission, and means for 'admitting pressure to the opposite side of said differential piston at variable points of travel of the main piston, an exhaust-valve mechanism and means operating said exhaust-valve mechanism out oi synchronism with the admision-valve.

VVAL'IER SABIN MCKINNEY.

Witnesses:

ALBERT H. GRAVES, FREDERICK C. GoonwrN. 

